Shears and tension-screw.



No. 844,903. f PATENTED FEB. 19, 1907.

- W. A. WILKINS.

$HEARS AND TENSION SCREW.

APPLICATION FILED SEPT.13.1906.

"Ilium TE Swank-L I Z/ A 565/7177:-

I album-n5 oNrrEn s' rn rns WILLIS A. WILKINS, OF EL PASO, TEXAS.

SHEARS AND TENSION-SCREW.

Specification of Letters Patent.

Patented Feb. 19, 1907.

Application filed September 13,1906. Serial No. 334,482.

tion, such as will enable others skilled in the art to which itappertains to make and use the same.

This invention has relation to shears provided with a tension-spring atthe pivotal or fulcrum point of the blades for maintaining a constanteven lateral pressure on the blades for the purpose of keeping theircutting edges in contact with each other at all times.

It is the purpose of the invention, in addition to what is hereinbeforestated, to pre vent the nut on the pivot-bolt, as also the latter, fromturning, thereby maintaining an even pressure on the tension-spring andpreventing the loss of the nut.

It is also the object of the invention to prevent the eyes orfinger-holes of the handlebars from coming together or in contact witheach other, thereby preventing the thumb or fingers from being pinchedbetween the eyes or from interfering with the action of the shears.

The annexed drawings, forming a part of this specification, show meansembodying my improvements, in view of which the invention will first bedescribed as to its construction and mode of operation and then bepointed out in the claims.

Of the said drawings, Figure 1 is a side ele vation of a pair of shearsembodying my im provement. Fig. 2 is a view of the opposite side at thefulcrum or pivotal point. Fig. 3 is an edge elevation. Fig. 4 is avertical sectional view through the parts of the fulcrumpoint. Fig. 5 isa sectional view showing the frusto-conical head of the pivot-boltlooking down on its inner side. Fig. 6 is a side view of the pivotboltwith the spring-adjusting nut turned thereon. Fig. 7 is a plan view atthe pivoted point, showing the socket in the blade and thetension-spring in place therein, the pivot-bolt being represented insection. Fig. 8 is a bottom plan view of the thumbnut.

Similar figures of reference designate similar parts or features, as thecase may be, wherever they occur.

giln the drawings, 10 designates one blade, and 11 the other blade, of apair of shears, which blades are fulcrumed or pivoted on a bolt 12,passing through both blades and located, preferably, about one-quarterof an inch or more from the handle end than from the points of theblades in order to increase the leverage of the handles when the shearsor scissors are used. The blade 1 l is'provided with a socket or recess13, having inwardlyinclined sides around the hole made through saidblade for the receipt of the shank 14 of the pivot-bolt 12, said socketbeing provided for the reception of the frusto-conical head 15 of thebolt, the outer surface of which is flush with the outer side of theshear-blade 11. The frusto-conical head of the bolt, or it may be theshank of the same, is provided with a lug 16, that is made tent in arecess 17 in the shear-blade to keep the bolt from turning in the holethrough the shear-blades when in proper position. The upper or 0ppositeblade 1.0 is provided with a round socket 18, into which is set a splitannular spring 19 with a hole through its center sufliciently large toadmit the pivot-bolt through, the outer or upper end of which isscrew-threaded to have the nut 20 turned thereon. The outside of thesaid nut is milled or otherwise constructed to make it a thu1nbnut,socalled, in order to obviate the use of a screw-driver in putting theparts together or taking them apart. The lower or inner end of thethumb-nut 20 is reduced in diameter or offset in order that the reducedportion 21 may enter the socket 18 and bear upon the spring 19 when thesaid thumb-nut is turned down on the screwthreaded portion of thepivot-bolt. The annular offset margin on the inner end of the thumb-nut,which is of greater diameter than the socket 18, rests or bears on theouter the margin of the said socket, and said marginal surface may beroughened, as at 22, as

may also the meeting surface of the nut, in order that when the nut isturned home on the pivot-bolt and bears on the shear-blade and spring itwill not be loosened or turned off by the action of the spring thereonin the operation of the shear-blades. The construction of the nut andsocket in the sh earblade just described are of importance in theinvention, as is also the construction of the frusto-conical head, itslug, and the socket in the side of the shear-blade 11, since thesefeatures insure the maintenance of the bolt-spring and nut permanent inposition after once having been adjusted. I

One of the handle bars of the blades is provided on its inner side witha sgnreinglug 23, the end of which is arlaptedv to come into contactwith the opposite hanole-bar, and so prevent the finger-eyes 24. of thehandles from coming together, and so pinching the thumb or fingers ofthe operating hand or allowing interference with the operation of theblades.

It is obvious that the improvements with. respect to the self-adjustingtension on the blades may readily be applied to the common form ofshears or scissors by taking out the old pivot-screw, filing away thethread. thereon where it passes through the blades, and making a smallinwardly-inclined recess in the shear-blade 11, and providing the head.of the bolt with a lug and a recess therefor, and fitting the upperblade 10 with a recess, as described, with a spring therein, andproviding a thumb-nut for the outer end of the bolt or screw of thecharacter described, and roughing the offset face of the bolt and themeeting surface of the shearblade, as explained.

The invention described. is at once simple in construction and efficientand ready of operation, obviating the use of a screwdriver to adjust itor put it together or take it apart, maintaining the bliLi'CS under thesame tension at all times until they are practically worn out, andpossessing other advantages hereinafter alluded to or made obvious bythe described construction and mode of operation.

In roughing the offset surface of the thumb-nut and the opposing surfaceof the shear-blade it may take the character of radial ribs and groovesof shallow form, so as to holdor lock the nut against the action of toospring. Ordinarily, however, the friction between the surface of theoffset part of the nut and the opposing surface of the blade will besufficient to hold the nut against being loosened by the tension-spring.'l he nut can be set down tight on the blade without un dulyincre asingthe stress of the tension spring.

The spring around the pivot-bolt might be a helical spring of well-knownform or a spring of other form and. subserve the purpose of the springshown and described as well, and. so other mechanical changes may bemade in the form and arrangement of parts without departing from thegeneral nature or spirit of the invention.

' What is claimed as the invention is- 1. The combination with theblades of a pair of shears or scissors, one of which is provided with asocket having inwardlytaper stereos -on the screw-threaded part of thebolt, and

having its inner end reduced to enter the socket of the other blade andbear upon the said spring the annular offset surface of the nut restingor bearing on. the surface of the last-mentioned blade around themargin. of the pivot-hole.

2. The combination with the blades of a pair of shears or scissors, oneof which is provided. with a socket having inwarilly-taper-' ing wallsand a recess, a smooth hole being formed through both blades, an annularsocket in the other blade, a spring in. said socket, a pivot-bolt havinga frusto-eonical head and lug adapted to fit the socket and recess inthe first-mentioned blade, and a smooth shank where extending throughthe pivot-holes of the blades but screw-threaded on its end, a thumb-nutadapted. to be turned on the screw-tlueaded part of the bolt, and havingits inner end reduced to enter the socket of the other blade and bearupon the said spring, the annular ofl'set surface of the nut resting orhearing on the surface of the last-mentioned blade around the margin ofthe pivot-hole, the surface of the offset POP tion of the nut and theopposing surface of the blade being roughened to lock or hold the nut inplace against the action of the spring.

'l he combination, with the shear-blades of the pivot-bolt having itshead secured in one blade, and provided with a shank smooth in the partthat extends through the blades and screw-threaded on its extended end,a round socket in the outside of the other blade, a spring surroundingthe shank of the pivot-bolt in said socket, a thumb-mrt turned on saidscrew-tlnezided part of the bolt, said tlnunb-nut being reduced indiameter and having an offset at its inner end, the reduced part beingadapted to enter the socket of the blade and bear upon the spring andthe oil set surface bearing on the outside surface of the blade on themargin of the socket.

4t. lhe combination, with. the shear-blades of the pivot-bolt having itshead secured in one blade, and provided with a shank smooth in the partthat extends through the blades and screw-threaded on its extended end,a round socket in the outside of the other blade, a spring surroundingthe shank of the pivot-bolt in said socket, a thumb-nut turned on saidscrew-threaded part of the bolt, said thumb-nut being reduced. indiaereter and having an offset at its inner end, the

In testimony whereof I aflix my signature in presence of twowitnesses.

WILLIS A. WILKINS.

Witnesses:

W. C. WHITE, I CHET. DEAN.

